Is Venus the two-faced cat really a chimera?

Genetics explained, with added kittens.

Venus the cat has been in the news. She has heterochromia – that is, her two eyes are different colours – as well as a perfectly placed black splodge (technical term), which makes her look like Popular Batman Villain Two-Face.

Why is she like that? One possibility is that she is a chimera. This term, taken from the mythical monster with the heads of a goat, lion and snake, refers to a real – albeit relatively rare – condition where two genetically distinct embryos merge in the womb.

A chimera is essentially the reverse of identical twins. In the latter, one fertilised egg splits completely and forms two separate embryos; in the former, two fertilised eggs merge together and grow into one child.

The cells which come from each of the fertilised eggs maintain their own character – so if one egg had genes for black hair and the other for white, the resulting chimera would have mottled black and white fur:

A chimeric rat with her babies. Photograph: Wikimedia commons

The thing is, Venus may not actually be a chimera.: her perfectly split face may just be a fluke placement of an otherwise normal tortoiseshell pattern. National Geographic's Katia Andreassi writes:

Female cats, said Leslie Lyons, a professor at the University of California, Davis, already have two X chromosomes so they can sport that coat without the extra X. That means Venus is not necessarily a chimera.

To find out would require genetic testing, said Lyons. With samples of skin from each side of the cat, "we can do a DNA fingerprint—just like on CSI—and the DNA from one side of the body should be different than the other."

But there is still a mystery about Venus - her single blue eye. Andreassi adds:

Cat eyes are typically green or yellow, not blue. A blue-eyed cat is typically a Siamese or else a cat with "a lot of white on them," she explained.

Venus appears to have only a white patch on her chest, which to Lyons is not enough to explain the blue eye.

Science: making cool cats cooler.

Venus the "chimera" cat.

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

@Simon_Cullen via Twitter
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All 27 things wrong with today’s Daily Mail front cover

Where do I even start?

Hello. Have you seen today’s Daily Mail cover? It is wrong. Very wrong. So wrong that if you have seen today’s Daily Mail cover, you no doubt immediately turned to the person nearest to you to ask: “Have you seen today’s Daily Mail cover? It is wrong.”

But just how wrong is the wrong Mail cover? Let me count the ways.

  1. Why does it say “web” and not “the web”?
  2. Perhaps they were looking on a spider’s web and to be honest that makes more sense because
  3. How does it take TWO MINUTES to use a search engine to find out that cars can kill people?
  4. Are the Mail team like your Year 8 Geography teacher, stuck in an infinite loop of typing G o o g l e . c o m into the Google search bar, the search bar that they could’ve just used to search for the thing they want?
  5. And then when they finally typed G o o g l e . c o m, did they laboriously fill in their search term and drag the cursor to click “Search” instead of just pressing Enter?
  6. The Daily Mail just won Newspaper of the Year at the Press Awards
  7. Are the Daily Mail – Newspaper of the Year – saying that Google should be banned?
  8. If so, do they think we should ban libraries, primary education, and the written word?
  9. Sadly, we know the answer to this
  10. Google – the greatest source of information in the history of human civilisation – is not a friend to terrorists; it is a friend to teachers, doctors, students, journalists, and teenage girls who aren’t quite sure how to put a tampon in for the first time
  11. Upon first look, this cover seemed so obviously, very clearly fake
  12. Yet it’s not fake
  13. It’s real
  14. More than Google, the Mail are aiding terrorists by pointing out how to find “manuals” online
  15. While subsets of Google (most notably AdSense) can be legitimately criticised for profiting from terrorism, the Mail is specifically going at Google dot com
  16. Again, do they want to ban Google dot com?
  17. Do they want to ban cars?
  18. Do they want to ban search results about cars?
  19. Because if so, where will that one guy from primary school get his latest profile picture from?
  20. Are they suggesting we use Bing?
  21. Why are they, once again, focusing on the perpetrator instead of the victims?
  22. The Mail is 65p
  23. It is hard to believe that there is a single person alive, Mail reader or not, that can agree with this headline
  24. Three people wrote this article
  25. Three people took two minutes to find out cars can drive into people
  26. Trees had to die for this to be printed
  27. It is the front cover of the Mail

Amelia Tait is a technology and digital culture writer at the New Statesman.